blood cells count

2. Haemocytometer
(chamber)

3. objectives
• What is hemocytometer?
• What are the uses of hemocytometer?
• Principle of cell counting?
• What are the common source of error
during cell counting?

4. haemocytometer
• Hemo: blood
• Cyto: cell
• Meter: measurement
Thus, it is an instrument used to count
the blood cells.

5. background
• The haemocytometer
was invented by Louis-
Charles Malassez.

6. Definition:-
• One of heamatological equipment
used in counting blood cells.

8. USES : -
• The use of haemocytometer counting
chamber in hematology lab for manual
counting of :
*White blood cells count.
*Red blood cells count.
*Platelets count.

9. Different types of Counting
chamber
• Ordinary Neubauer counting chamber
• Improved Neubauer counting chamber
• Levy’s counting chamber
• Fuch’s Rosenthal chamber

10. It includes:
Neubauer’s
slide
Cover slip
Diluting
pipette
Cover glass

11. NEUBAUER’S SLIDE
• Thick glass slide with two ruling area
on centre.
• Ruled area are separated by H-shape.
• Beyond the two vertical arm of
trough there are two raised
shoulder(ridge) which support cover
glass.
• lining is coated by shining metal or
rhodium.

14. • Each scale is 3mm wide and 3mm long.
• Depth of the chamber is 0.1mm
• The whole scale is divided into 9 big
squares.
• Each square is 1mm long and 1mm wide.

16. Hemocytometer
(Chamber)

17. • The four corner squares are
further divided into sixteen smaller
squares and are used for WBC
counting.

18. Four
corner
squares
are
meant
for WBC
counting.
Total =
64 small
squares
W
W
W
W

20. • Central square is divided into 25
medium sized square and are
separated by triple line
• The medium sized square are further
divided into 16 small square(tiny)
• The four corner and central square
are used for platelet and RBC count.

22. • Do not count cells touching
– Bottom line
– Right line
Counting Rule(L-shape)

24. Counting rule

26. Cover slip
• Special cover glass with smooth
surface and even thickness
• Thickness= 0.3, 0.4, 0.5 mm
• Length= 16x22mm, 22x23mm

27. The grid area of chamer = 9 mm2
.
The depth of chamber = 0.1 mm .

28. Hemocytometer Chamber
• Depth = 0.1 mm
• Grids = 9 mm2 .
– RBC use 5 small squares
in the center large square
– WBC use 4 corner large
squares

29. Principle
• Dilution of blood.
• Sampling of diluted suspension into
measured volume.
• Counting of cell in that volume.

30. Method : -
1: Clean the chamber and make sure
the central grid area of the
chamber and the special
haemocytometer cover glass are
completely clean and dry .
2: Attach the cover glass into position
over the grid area and press down
on each side until rainbow colours are
seen .

32. 3: Dry underside of the chamber and
place on the microscope stage .
4: In WBC’s count using 10 x objective
with condenser iris closed to give a
good contrast.
5: In RBC’s and PLTs count using 40 x
objective with condenser iris in
center to give a good contrast .

34. FOCUSING
• 4X to see the general
formation of chamber.
• 10X for WBC counting.
• 40X for RBC/Plt.
counting

36. Calculation
Cell count=
No of cells counted x dilution factor
volume( depth x area counted)

38. Sources of error
False high count False low count
• Improper mixing.
• Uneven distribution of cells.
• Error in pipetting.
• Error in calculation.
• Blood taken from area of
hemo concentration.
• Yeast, dirt and leucocyte
are counted as RBC.
• Blood diluted with tissue
fluid.
• Undue delay in counting of
cell.
• Clumping of cell.
• Uneven distribution of cell
• Faulty technique of
counting.
• Improperly standarized
counting chamber.